1. Field of the Invention
This invention relates generally to the field of vehicle travel surface condition monitoring and control systems, and more particularly to a vehicle mounted and/or stationary positioned system for determining characteristics of surface materials related to adverse driving conditions which includes a vehicular mounted weather monitoring subsystem for measuring weather conditions at the vehicle location.
2. Description of the Related Art
Stationary weather stations have weather vanes and wind velocity meters to provide wind direction and speed information (velocity), and sensors to provide relative humidity, air temperature, and precipitation amounts and rates, among other parameters, to local and remote locations. Some aircraft also have been equipped with similar equipment to monitor conditions in thunderstorms and hurricanes. However, such instrumentation has commercially not been installed on motor vehicles.
Road condition service vehicles such as snow plow trucks and surface conditioning vehicles which deposit materials such as sand and chemicals such as salt to travel surfaces depending on the current or predicted road surface conditions do not carry weather analysis equipment on board. Proper surface conditioning materials are optimally applied during the early stages of adverse weather conditions as well as throughout the adverse weather condition. However, the optimal distribution of materials and compositions change dramatically as the storm progresses through a locality. Currently there is no real time weather sensing apparatus available that can be vehicle mounted which determines weather conditions such as wind speed and direction, temperature, humidity, precipitation events, water content and rates of deposition, and barometric pressure.
A number of attempts have been made to sense the conditions of roadways, aircraft runways, and other surfaces for vehicular traffic, during changing adverse weather conditions For example, it is known to place conductivity, temperature and other sensors either in the road surface or adjacent the road to monitor the temperature of the road surface, the subsurface temperature and/or monitor whether there is ice forming on the surface. Atmospheric sensors may also be provided adjacent the road. This information can then be fed to a central location for control and dispatch of trucks to apply salt or sand or other deicing mixtures. At airports these types of warning systems are used to inform maintenance crews that the runways need to be treated or alert the staff that deicing procedures need to be implemented. Some conventional systems have a supply of chemicals and pumps beside the roadway or runway to automatically spray the road when triggered by a sensor.
There is also a need for such a warning system on road vehicles such as cars, buses and trucks to detect pending adverse conditions. However, available mobile systems are limited to basic moisture detection and temperature monitoring systems. Some examples of such systems are disclosed in U.S. Pat. Nos. 4,492,952 and 4,678,056. One particular system, disclosed in U.S. Pat. No. 5,416,476, employs an infrared sensor which is mounted on the exterior of the vehicle and sends a signal to a microprocessor which then can display the temperature of the road surface. These systems are simplistic and do not tell the operator the critical information needed under all conditions, such as, what is the composition of and at what temperature will the particular material actually on the road surface freeze? Therefore there is a need for an on board material sensing apparatus and system for determining when an actual liquid on a road surface will freeze in view of current weather conditions at the vehicle location and alerting the operator to such adverse driving situations before they actually occur so that the operator can adjust material spreading techniques and strategies accordingly.
There is also a need for a mobile mounted sensing apparatus and system for use by road crews to evaluate current local weather conditions and determine and evaluate existing materials, if any, on a road surface in order to determine the optimal amount, type and timing of additional material to be applied to the surface in order to reduce the current and future hazardous driving conditions.
There is also a need for an apparatus and system for predicting, displaying and sometimes controlling the distribution of travel surface conditioning materials available on board local road crew trucks based on current and predicted local weather conditions at the travel surface location. Such a system is unavailable today.